The present invention relates to electronic plumb indicators for monopoles, survey poles, global positioning antennas and the like.
There is a need in the surveying art and the global positioning (GPS) art to increase the speed and accuracy at which surveying poles and GPS antenna poles are plumbed to vertical positions.
Broadly stated, the present invention encompasses a plumb indicator comprising a substrate, a plumb bob suspended by a thread (e.g., wire, cable, string, etc.) and disposed over a first surface of the substrate, and a probe. The substrate has an array of conductive pads disposed over its first surface, preferably in a regular pattern. The probe has a first body portion in contact with a surface of the plumb bob, and a conductive tip disposed between the plumb bob and the first surface of the substrate. The probe tip makes contact with the first surface of the substrate, and contacts one or more pads in normal operation. The pads may be scanned electronically to determine the location of the probe tip and plumb bob with respect to the substrate.
In preferred embodiments of the present invention, the plumb bob comprises an elongated mass and cylindrical bore along a portion of the vertical center axis of the elongated dimension. Also in these preferred embodiments, the first body portion of the probe comprises a cylindrical shaft which is disposed within the cylindrical bore in the plumb bob, and the tip of the probe has a rounded or flat surface for contact with the first surface of the substrate.